GTINs are licensed by GS1 UK rather than sold. The ownership of the numbers, therefore, remains with GS1 UK and the numbers issued to a member cannot be sold to anyone else.
Licensing the numbers in this way ensures the ongoing integrity of GS1’s standards and works to the benefit of everyone. It ensures the uniqueness and traceability of the numbers, which is essential for selling in store, online and moving things through the supply chain.
Several retailers and online marketplaces verify that businesses are using GTINs that are licensed to them through GS1 membership. If numbers are obtained from other sources it can prevent you listing products with them.